In April 2021, the Ninth Circuit issued its panel opinion in Wholesale Grocery Cooperative v. Bumble Bee Foods LLC, which held that the district court erred in certifying several classes of tuna purchasers in an antitrust class action because it failed to resolve the parties’ dispute over whether the plaintiffs’ class-wide damages model “mask[ed] individualized differences” between putative class members. In reaching this conclusion, the Ninth Circuit held that a district court cannot certify a class unless it includes only a “de minimis” number of uninjured class members. It also emphasized that the district court could not determine whether individualized issues predominated without first resolving the “factual disputes as to how many uninjured class members are included in Plaintiffs’ proposed class,” even if those disputes also bear on the merits. In April 2022, however, the Ninth Circuit issued a split en banc opinion in which it rejected the panel majority’s “de minimis” requirement and held that the district court did not err in certifying a class. The en banc opinion—which not only rejects a “de minimis” standard, but also discourages district courts from resolving merits issues at the class certification stage— deprives defendants in the Ninth Circuit of a critical weapon to oppose the certification of overbroad classes.